This invention relates to polyphosphates and their use in controlling the growth of bacteria. In particular, this invention relates to the use of antimicrobial polyphosphates to control the growth of bacteria in foods or during food processing.
In this specification and claims, unless the context indicates otherwise, xe2x80x9cfoodxe2x80x9d means any liquid, solid, semi-solid, dispersion, suspension or emulsion, including those controlled by the Federal Food, Drug and Cosmetic Act, which are consumable by mammals (including animals and humans), fish and other marine life, and fowl, whether or not having nutritive value, and which are susceptible to microbial growth. xe2x80x9cFoodsxe2x80x9d therefore include proteinaceous substances and/or carbohydrates, beverages, edible oils and water, including directly consumable water, e.g., bottled water, and water used to prepare, process or transport other food forms.
Bacterial contamination of food is a major problem in the food processing industry. Bacteria must be controlled throughout the food processing process, for example: (1) surface treatment of foods to disinfect the surface and kill spoilage organisms and pathogens located on the surface of the food; (2) in food processing plants, such as dairy, meat, and poultry processing facilities, to kill spoilage organisms and pathogens in the food processing equipment; and (3) in the processed food to prevent the growth of spoilage organisms and pathogens during distribution and storage.
Strong oxidants, such as peracetic acid and hydrogen peroxide are used to control bacteria in food processing plants. See, for example, Chen, U.S. Pat. No. 5,641,530, which discloses the use of mixtures comprising hydrogen peroxide as disinfectants in food-related applications. However, strong oxidants pose a hazard to the user because they can attack the skin. Hydrogen peroxide cannot be incorporated into processed food to protect it from bacterial contamination and growth during storage and distribution. Peracetic acid solutions are acidic and can corrode equipment. Peracetic acid decomposes to acetic acid, which can adversely affect the taste and odor of the food. Other cleaning products typically have a pH of 10.5 to 12 and are likely to damage the skin, eyes, and respiratory passages upon contact or inhalation.
Guthery, U.S. Pat. No. 5,364,650, discloses a method for disinfecting animal carcasses by dipping them in a solution comprising aliphatic medium chain fatty acids, a chelating agent, and hydrochloric acid. This solution is acidic and potentially harmful to the skin, eyes, and respiratory passages. Bender, U.S. Pat. No. 5,635,231, discloses a method for disinfecting animal carcasses by treating them with an alkali metal orthophosphate and steam. This method is difficult to use because of the need to generate steam and the high concentration of alkali metal phosphate required for efficacy.
Lactic acid and its sodium and potassium salts are incorporated into food as antimicrobials. However, at least 2% by weight, and typically 3% by weight, of lactic acid is required, which can adversely affect taste. If lactic acid is added, the lowered pH produced by the added lactic acid can also reduce the water holding capacity of meat.
Thus, a need exists for non-corrosive materials that can be used to control bacteria on the surface of food, in food processing plants, and that can be incorporated into food to protect it from bacterial contamination and growth during storage and distribution.
It has been discovered that treatments of alkali metal orthophosphate, tripolyphosphate, acid pyrophosphates, polyphosphate, and pyrophosphate, either singly or as mixtures thereof, can be used to reduce and control various classes of microorganisms, specifically those important to the safety and spoilage of food during processing, storage, and distribution. Gram-negative organisms belonging to, but not restricted to, the genera Escherichia, Salmonella, and Pseudomonas, are generally adversely affected by compositions that are alkaline and contain polyphosphates. Gram-positive organisms belonging to, but not restricted to, the genera Staphylococcus and Listeria are generally adversely affected by compositions that contain polyphosphates and are alkaline or neutral. Because these compositions control pathogens at near neutral pH conditions using very dilute preparations, the physicochemical changes (color, texture, flavor, nutrient retention) that may occur at highly alkaline or highly acidic conditions are reduced. These compositions are safer to handle and have fewer disposal problems than highly alkaline or highly acidic compositions.
These compositions can be used in food-related applications, including: cleaning compositions to disinfect the surface of food and to clean and disinfect equipment used in food processing and solutions to be added to food to inhibit the growth of microorganisms responsible for foodborne diseases and spoilage during distribution and storage.
Optionally, the compositions may contain at least one organic acid and/or at least one salt of an organic acid, for synergistic antimicrobial action in foods.